The invention is designed to improve a splice in a piece of elastomeric material, especially a strip of white sidewall after it has been applied to an unvulcanized tire. Strips of white sidewall rubber, covered by black rubber, are usually the last components to be positioned on the unvulcanized tire. The opposing ends of a strip are matingly cut on an angle along a line which is normal to the longitudinal axis of the strip. The cut ends are abutted together and hand-stitched down against the unvulcanized tire. It has been found that such splices occasionally open up or come apart when placed under the stresses encountered during molding of the tire. An opened splice creates an unsightly defect in the finished tire from an aesthetic standpoint. The invention is directed to solving this problem by providing a highly improved splice which will not come apart under the stresses normally experienced by the splice.
Briefly stated, the invention is in an apparatus for splicing together opposing angularly cut ends of a strip of elastomeric material used in the building of a tire. The apparatus comprises a resilient cushion which is positionable on one side of the splice adjacent the spliced ends of the strip. A pad is mounted in spaced relation from the cushion, and means are provided for causing relative movement between the pad and cushion to compress the spliced ends of the strip between them. Other means are supplied for heating the pad to correspondingly heat the elastomeric material of the spliced ends sufficiently to cause a physical and chemical bond between the spliced ends.
The spliced ends, so to speak, are welded together to form a unitary integral structure where the splice once was. Such a unitary structure will not tear or come apart under stress, as do conventionally made splices. Sometimes, a hot knife is used to sear the outer surface of a splice to help hold the spliced ends together, but even in such cases the splice still exists and is susceptible to coming apart under stress.